Hydraulic control device for a gear box



March 6, 1962 JEAN-PAUL BRUNOT 3,023,641

HYDRAULIC CONTROL DEVICE FOR A GEAR BOX Filed May 20, 1959 3Sheets-Sheet 1 March 6, 1962 JEAN-PAUL BRUNO-1" 3,023,641

HYDRAULO CONTROLJ DEVICE FOR A GEAR Box Filed May 20, 1959 5Sheets-Sheet 2 1% Maw.,

March 6, 1962 JEAN-PAUL BRUNOT Filed May 20, 1959 HYDRAULIC CONTROLDEVICE FOR A GEAR. BOX

3 Sheets-Sheet 3 A M' u/ United States Pater ice 3,023,641 HYDRAULICCONTROL DEVICE FOR A GEAR BOX Jean-Paul Brunot, Sens, France, assignerto Compagnie de Pont-a-Mousson, Nancy, France, a French body corporate yFiled May 20, 1959, Ser. No. 814,527

Claims priority, application France May 23, 1958 7 Claims. (Cl. 74--75)The present invention relates to the hydraulic control of road and railvehicle gear boxes which are of the type having gears always in mesh andin which the speeds are engaged by the immobilization of one or twoelements of the gear box and/or by the interconnection of two elements.

A gear box of this type comprises brakes and clutches actuatedhydraulically by rams which are supplied with oil under pressure by oneor two pumps driven by the engine shaft and by the driven shaft of thegear box. Consequently, the speeds can only be engaged when the pump orpumps are operating,

The object of the invention is to permit engagement of a speed ratioeven when the pump or pumps are inoperative, that is, independently ofthe normal hydraulic circuit.

The invention provides an auxiliary control device for a gear box of theaforementioned type, this device, which permits the engagement of aspeed of the gear box when its driving and driven shafts are staionary,comprising in combination an alternating movement pump which is suppliedwith oil from a reservoir having a pressure head and is actuated bymanual operating means, and a ram supplied with oil under pressure bythe pump and adapted to permit, when supplied with the oil, engagementof said speed.

Another object of the invention is to provide an assembly of a hydrauliccontrol device for a gear box of the aforementioned type, said controldevice comprising in combination a main hydraulic control device havingrams and supplied by at least one pump controlled by a supply'selector,and the aforementioned auxiliary control device whose single ram isconnected in parallel with one of the rams of the main control device.

The two rams could be either coaxial or side by side to act on the sameend of a speed engaging element or so disposed that one acts on one endand the other on the other end of a iioating speed engaging element.

Further features and advantages of the invention will be apparent fromthe ensuing description with reference to the accompanying drawings towhich the invention is in no way limited.

In the drawings:

FIG. 1 is a diagrammatic sectional view of a complete control deviceconsisting of a main device and an auxiliary device according to theinvention, having coaxial rams;

FIG. 2 is a partial sectional view of a modiiication in which the ramsare disposed in side by side relation.

FIG. 3 is a sectional view taken along line 3 3 of FIG. 2, and

FIG. 4 is a view similar to FIG. 1, the rams co-operating with the twoends of a oating brake element.

In the embodiment shown in FIG. 1, the invention is applied to a brakingdevice for an element of an epicyclic gear box for engaging a speedratio, for example the second speed of the gear box.

Let it be supposed that an element or gear 1 of a gear box-only thehousing 2 of which has been showndisposed at the end of the case of theengine M is to 3,023,641 Patented Mar. 6, 1962 be immobilized. For thispurpose, there is provided a exible brake segment or element 3 in theform of an open collar surrounding and concentric with the element 1.One of the ends of the segment 3 is fixed to the housing 2 at 4 and theother end 5 is hooked to the stem or rod 6 of a piston 7 pertaining to amain ram V actuating the segment 3. The piston 7 slides in a cylinder 8which has a vertical axis and is rigid with the housing 2, this cylinderbeing open at its end adjacent the stem end of the piston 7 and closedat the other end by a special cover 9. This piston is hollow and iscaused to Slide in the cylinder 8, in opposition to the action of aspring 10 compressed between the end of the cylinder 8 and a face of aflange provided on the piston 7, by the action of oil under pressure.The latter is supplied through a main pipe 11 which extends through thecover 9 and is connected, for example, through the medium of a speedselector S to a single oil pump P1 driven by the driving or driven shaftof the gear box. In the presently-described embodiment, this pump P1 islocated within the case of the engine M and its shaft 23 is connected tothe engine shaft (not shown) which constitutes the input shaft of thegear box.

Disposed within the main ram V and in coaxial relation thereto is anauxiliary ram W. The cover 9 is mounted by a cylindrical skirt 12 whichis coaxial with the cylinder 8, open at both ends, and located withinthe piston 7 which is hollow. Slidable in the skirt or cylinder 12 is afreely disposed piston 13 which is adapted to cause the piston 7 to moveunder the elfect of the pressure of the oil supplied by an auxiliarypipe 14 extending through a screw-threaded plug 15 screwthreadedlyengaged in the cover 9. In its inoperative position of rest, the piston13 is carried by the plug 1S.

rThe pipe 14 is connecetd to a pump P2 or an auxiliary master cylindercomprising a cylinder 16 which is connected by a pipe 17 to an oilreservoir having a pressure head relative to the cylinder 16. A piston19 is movable in the cylinder 16, under the effect of a push rod 20actuated by a pedal 21 pivotably mounted on a fixed pin 22, inopposition to the action of a spring 23 compressed between the piston 19and the end wall of the cylinder 16.

The device operates in the following manner:

When the engine of the veln'cle is running and the driver wishes toengage a speed of the gear box, he operates the speed selector S in suchmanner as to supply oil under low pressure by way of the pipe 11directly into the main ram V. The oil raises the piston 7, the rod 6 andthe hook 5 and thus moves the two ends of the brake segment 3 towardeach other and causes the segment to tighten round the element 1. Theselected speed ratio is thus engaged. During this time, the piston 13 ofthe auxiliary ram W remains inoperative.

When the driver wishes to change speed, the pipe 11 is connected to theoil exhaust and the spring 10 returns the piston 7 to its initialposition and thereby untightens the brake segment 3.

When the engine of the vehicle is not running and cannot be started upby the starter and the driver wishes to engage the second speed by meansof the ram including the piston 7, for example for the purpose of towinghis vehicle, he depresses the pedal 21 in such manner as to exert forceon the piston 19 of the cylinder 16 and thus delivers oil under highpressure through the pipe 14 and into the cylinder 12 of the auxiliaryram W. The piston 13 is then raised. It in turn raises the piston 7 ofthe main ram V and this tightens the brake :waas/i1 Segment 3 andengages the speed in the previouslydescribed manner. The drivercontinues to exert pressure on the pedal 21 until the engine has startedup. When this has been obtained, the oil pump P1 of the engine once moreoperates and supplies oil under pressure through the pipe 11. Thispressure of oil acting on the piston 7 of the main ram V substitutesitself for that acting on the piston 13 of the auxliary ram W. Thedriver then releases the pedal 21 which is returned to its initialposition by the action of the spring 23. The cylinder 12 is partiallyemptied and the piston 13 returns to the plug 15 Thus by means of theinvention, which provides a ram W and an additional or emergency oilsupply, the engagement of the speed of the gear box is always possibleeven when the engineis not running and the main ram V cannot be directlysupplied with oil under pressure.

Owing to its small volume, the cylinder 12 of the auxiliary ram W israpidly filled with a single stroke of the pedal 21 and this enables thedriver to actuate the device of the invention Without fatigue and to actquickly if required.

The driver can therefore use the auxiliary device (W, P2) as anemergency brake by engaging the second speed controlled by this deviceeven if another speed, for example the third or fourth speed, of thegear box is still engaged, which has for eliect to immediately block thegear box and energetically brake the vehicle.

FIGS. 2 and 3 show a modication of the invention in which the auxiliaryemergency ram Wl is located outside the main ram V, the rods 6 and 6a oftheir pistons 7 and 13a, movable in the cylinders 8 and 12a, acting onthe ends 5 and 5a of two brake segments or elements 3 and 3a each ofwhich surrounds half the width of the gear box element or gear 1.

If desired, the two segments 3 and 3a could form a single segmentcapable of being actuated by one and/or the other of the rams V and We.

In the embodiment shown in FIG. 4, the main ram V and auxiliary ram Wbare so disposed as to act on the opposite ends of the same brake segmentor band 3, which is therefore no longer hooked on a projection of thehousing 2 as in the rst two embodiments. In this modification, theauxiliary ram Wb must be bigger than that of the first two embodimentsand must be supplied with liquid at a higher pressure since thetightening force to be exerted on the end 4 of the segment must begreater than in the first two embodiments in view of the direction ofrotation of the element 1 indicated by the arrow f in FIGS. 1 and 4'.

Although specificY embodiments of the invention have been described,many modiiications and changes may be made therein without departingfrom the scope of the invention as defined in the appended claims. Y

Thus the invention is also applicable to actuation of a clutch 0r twobrake bands or segments simultaneously or to actuation of a brake bandand a clutch when these elements are required for engaging a speed.

' Having now described my invention what I claim as new and desire tosecure by Letters Patent is:

l. In a hydraulic control device for a gear box which has speed engagingelements actuated hydraulically, in combination: on the one hand, a mainhydraulic control device comprising main rams for actuating said speedengaging elements, and, on the other hand, an auxiliary control devicefor engaging one of the speeds even when the main control device isinoperative, said auxiliary control device comprising a pumphaving analternating movement, a reservoir for supplying liquid to said pump,means capable of an alternating movement for manually actuating saidpump, and an auxiliary ram supplied with oil Vunder high pressure by thepump and so disposed relative to the speed engaging element engagingsaid speed that when the auxiliary rarn is supplied with said i oil itactuates the speed engaging element in the direction for engaging saidspeed,

2. In a hydraulic control device for a gear box which has speed engagingelements actuated hydraulically, in

combination: on the one hand, a main ram for actuating one of said speedengaging elements for engaging the corresponding speed, a pump driven bysaid gear box for supplying liquid under low pressure to the main ram,and a selector for connecting the output end of the pump selectively tothe main ram, and, on the other hand, an auxiliary control device forengaging said speed even when the pump is inoperative, said auxiliarydevice comprising an alternating movement pump, a reservoir forsupplying liquid to said alternating movement pump, means for supplyingthe liquid to the latter, means capable of alternating movement formanually actuating the alternating movement pump, and an auxiliary ramsupplied with oil under high pressure by the last named pump, and sodisposed relative to the speed engaging element engaging said speed thatwhen it is supplied with said liquid it causes the actuation of saidVengaging element for engaging said speed.

3. Hydraulic control device as claimed in claim 2, wherein saidauxiliary ram is disposed within said main ram so that when it issupplied with liquid it actuates the speed engaging element in thedirection to engage said speed.

4. Device as claimed in claim 3, wherein the main and auxiliary rams areof the type having a cylinder and piston, the piston of the main rambeing hollow and providing a housing for the auxiliary ram whose pistonis so adapted that when it is subjected to the pressure of the liquid itbears against the piston of the main ram.

5. Device as claimed in claim 4, wherein a cover closes the cylinder ofthe main ram and carries within the cylinder of the latter a skirtportion constituting the cylinder of the auxiliary ram.

6. In a hydraulic control device for a gear box which has speed engagingelements actuated hydraulically, in combination: on the one hand, a mainram for actuating one of said speed engaging elements for engaging thecorresponding speed, a pump driven by said gear box for supplying liquidunder low pressure to the main ram, and a selector for connecting theoutput end of the pump selectively to the main ram, and, on the otherhand, an auxiliary control device for engaging said speed even when thepump is inoperative, said auxiliary device comprising an alternatingmovement pump, a reservoir having a pressure head relative to the pumpfor supplying the liquid to the latter, means capable of alternatingmovement for manually actuating the alternating movement pump, and anauxiliary ram supplied with oil under high pressure by the last namedpump and so disposed relative tothe speed engaging element engaging saidspeed that when it is supplied with said liquid it causes the actuationof said engaging element for engaging said speed, said speed engagingelement being divided into two parts in parallel relation to oneanother, and thermain and auxiliary rams being disposed in side by siderelation so as to act on the adjacent ends of said two parts ofthe speedengaging element.

7. In a hydraulic control device for a gear box which has speed engagingelements actuated hydraulically, in combination: on the one hand, amainram for actuating one of the speed engaging elements for engaging thecorresponding speed, a pump driven by said gear box for supplying liquidunder low pressure to the main ram, and a selector for connecting theoutput end of the pump selectively to the main ram, and, on the otherhand, an auxiliary control device for engaging said speed even when thepump is inoperative, said auxiliary device comprising Yan alternatingmovement pump, a reservoir having a pressure head relative to the pumpfor supplying the liquid to the latter, means capable of alternatingmovement for manually actuating the pump, and an auxiliary ram suppliedwith oil under high pressure by the pump, and so disposed relative tothe speed engaging element engaging said speed that when it is suppliedwith said liquid it causes the actuation of said speed engaging elementfor engaging said speed, the main and auxiliary rams being so disposedthat one ram acts on one end and the other ram acts on the other end ofthe speed engaging element.

References Cited in the le of this patent UNITED STATES PATENTS LinsleyMay 11, 1937 Weiss Aug. 16, 1938 Evernden Apr. 10, 1951 Holman Aug. 18,1953 Euga Feb. 3, 1959

